Telephone system



E. CURNUTT.

TELEPHONE'SYSTEM.

APPLICATION FILED 16.14, 1917.

1 1,378,585; Patefited May 17, 1921.

3 SHETSSHEET I.

INVENTOR amen @rnull ATTORNE E. CURNUTT.

TELEPHONE SYSTEM.

APPLICATION EILED AUG.I4. 191?.

Patented May 17, 1921.

3 SHEETSSHEET 2.

INVENTOR Hmer Qunult W BY @g I ATTORNEY WITNESSES E. CURN UTT. TELEPHONE-SYSTEM.

APPLICATION FILED AUG-I4, 19H.-

ATTORNEY UNITED STATES ELMER CURNUTT, OF GARNETT, KANSAS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Application filed August 14, 1917. Serial No. 186,205.

To all whom it may concern:

Be it known that I, ELMER' CURN rr'r, a citizen of the United States, residlng at Garnett, in the county of Anderson and State of Kansas, have invented certain new and useful Improvements in Telephone Systerns, of which the following is a speclfication.

This invention has relation to telephone systems, and has for an object to provide a telephone system for a rural party l1ne,'embodying means whereby to prevent other subscribers than the one called from listening in.

Another object of the invention is to provide a party line telephone system having the above named characteristics and embodying means for permitting only the bell of the called subscriber to ring, the remalning bells of the party line remaining silent.

A still further object of the invention is to provide a party'line telephone system and apparatus embodying means whereby each subscriber may be aware when the line is in use by means of an indicating device, without however, being permitted to listen in, the indicating device also informing the subscribers to the line when the conversation has ceased and the line is again free.

In addition to the foregoing my invention comprehends improvements in the details of construction and arrangement of the parts to be hereinafter more fully described and particularly set forth in the appended claims. V

In the accompanying drawings in whlch similar and corresponding parts are designated by the same characters of reference throughout the several views in whlch they appear:

Figure 1, is a view in perspective of a subscribers set of a party line telephone system constructed in accordance with my invention. Y

Fig.2, is a detail view of the mechanism for operating the indicator.

Fig. 3, is a view in side elevation of a switch employed in connection with my 1nvention. 1

Fig. 4, is a diagrammatic view of the shaft. of the magneto generator used in my system. v

Fig. 5,is a diagrammatic view illustrating the winding of the magneto generator armature and Fig. 6, diagrammat c view of the wiring of two stations of a party line system, embodying my improvement.

With reference to the drawings, particularly Fig. 1, 10 indicates a casing designed to inclose the instrument of a subscribers set. A dial 11 is set in the front plate of the 'caslng, graduated in accordance with the number of subscribers on the line. A shaft 12 extends through the center of the dial and supports a hand 13 movable thereover as shown more in detail in Fig. 2. Said shaft 12 also carries fixedly mounted thereon a ratchet wheel 20. A lever 21 is fulcrumed at a point intermediate its ends as at 22 adjacent the periphery of the ratchet wheel 20, and said lever carries at each end a pawl 23 which engages the periphery of the ratchet wheel. Springs 24 secured to the lever and engaging the pawls tend to"urge the pawls into such engagement. A pair of stop pins 25 are located in the position to be engaged by said pawls 'when the lever 21 is shifted in a certain direction.

An operating mechanism for said'pawls and lever is provlded and includes an elec- Patented May 17,1921. 2

tro-magnet indicated generally at 26 com prising poles 27 and 28 connected by means of a yoke 29. Mounted for oscillation adjacent the ends of the poles is an armature 30 in the nature of a steel magnetized bar fulcrumed at a point intermediate its ends as at 31 upon a bracket 32. An arm is rigidly secured in said armature,said arm being indicated at 38, and extends between the poles of the electro-magnet and between a pair of leaf springs 34 which tend to centralize the armature 30 or to dispose the same in a mid-way position to retain the bar out of engagement with the poles of the magnet. A link 35 connects one end of the armature to the lever 21 whereby said lever may be oscillated when the armature is vibrated through energization of the electromagnet as will be presently explained. .A yoke 36 is mounted adjacent the electro-magnet with a magnet 37-supported in the intermediate portion thereof with the pole of the magnet extending between the terminals of said yoke as indicated in Fig. 2. One terminal 38 of the yoke is slotted to receive a sliding leaf 39 which is guided in x tically or horizontally. The end of the leaf 39 opposite to its supported end is bifurcated to embrace the end of the armature 30 to which the link 35 is connected. The slot 39 provided by the bifurcated end of the leaf 39, is longer than the width of the ar- .matiue 30 as shown in Fig. 2 of the drawing, so that some longitudinal movement of the leaf 39 is permitted independently of the connection to the armature 30. The other terminal of the yoke 36, which terminal is indicated at 40 supports a spring plate 41 acting as an armature disposed above the pole of the magnet 37. Said armature 41 lies in the same horizontal plane as the leaf 39 so that when said armature 41 is attracted by its magnet 37 so as to dispose the armature below the plane of the leaf 39, said leaf may be shifted to dispose the same above the armature 41 to hold said armature in engagement with the magnet. The armature 4]. is insulated from the yoke 36 for a purpose which will be presently noted.

I have illustrated in Fig. 3 of the drawings a type of switch employed in my system comprising a plurality of contact plates and buttons for flexing a number thereof in unison for the establishment of certain circuits. The switch comprises a relatively long plate 42- having terminals 43 and 44 bent downward. A pair of contact plates 45 and 46 are located beneath the plate 42 adjacent the ends thereof in parallelism thereto and normally engaging the downturned ends of said plate 42. A second long plate 47 is then disposed beneath the said plates 45 and 46 in parallelism thereto, the ends of said plate 47 being bent downward as at 48 and 49. A pair of short spring plates 50 and 51 are next disposed beneath the ends of said plate 47 in contact with the downturned terminals of said plate, and beneath these short plates a third long plate 52 is provided having downturned ends 53 and 54. A third set of short contact plates 55 and 56 are next located beneath the ends 53 and 54 of the plate 52, and a long plate 58 is located between the plate 52 and said plates 55 and 56, the plate 58 however, having its end straight and not curved as in the case of the long plates previously mentioned. A straight plate 59 similar to the plate 58 is next disposed beneath the plates 55 and 56 normally out of contact therewith. A long plate 60 is next disposed beneath the plate 59, and a last plate 61 is disposed beneath the plate 60 with the terminals of said plate 61 indicated at 62 and 63 bent upward, but normally out of engagement with said plate 60. The inner ends of the short plates of each verticalseries are connected together or held in blocks of insulation 64, and the outer terminals of each vertical series of short plates are connected together by means of studs of insulation 65 which are provided with buttons 66 and 67 which extend through the front of the casing as shown in Fig. 1.

I provide a novel form of magneto generator, the parts of which are shown in Figs. 4 and 5, and include a shaft 68 having a split ring commutator 69 mounted thereon. The armature coil indicated diagrammatically at 7 0 in Fig. 5 has its-terminals connected tothe segments of the commutator. One end of the shaft also carries a collector ring 71 insulated from the shaft and-one terminal of the armature coil is connected to said ring and the other is grounded upon the shaft 68. Brushes 72 and 73 engage the split ring commutator to collect the current therefrom, while a collector brush74 bears against the collector ring 71, another brush shaft for alternate engagement with contacts 79, 80 and '81, stationarily mounted, the contacts 79 and 81 being connected together as indicated. The shaft 68 isvjournaled for longitudinal sliding movement as well as rotarymovement whereby the contacts 77 and 78 may be shifted from engagement with the contacts 80 and 81 to a position where they engage the contacts 79 and 80 for. the purposes ofreversing the current in acircuit for a purposewhich will'be presently noted.

With reference to Fig. 6, A and B designate two stations on a party line connected by means of the main leads 82 and 83. Each station includes the same apparatus condescription of one will sufiice for all. A conventional type of pivoted receiver hook 84 is connected at its pivotal point by means of a conductor 85 to one contact 86 of a pair of contacts 87, the other contact being designated 88. Thesecontacts are associated with the mechanism shown in Fig. 2, and are designedto be brought into engagement by means of a cam 89 which is fixedly mounted upon the shaft 12. A conductor 90 forms the connection between the contact 86 and the yoke 36 shown in Fig. 2. The spring plate armature 41 is then connected by means of a conductor 91,t0 the main lead 82, and a conductor 92 is used to connect the contact 88 of the pair 87 mentioned above to said conductor 91 as indicated. A conductor 94 extends from one terminal of a transmitter 95 to the primary 101 of an induction coil and the other terminal of the transmitter is connected by means of a conductor 96 to a contact 97 located above the receiver hook 84 and normally out of contact with said hook when the receiver is restedupon the hook. A source of current 98 is interposed in said conductor 96. A contact 99 is also located above the receiver hook adjacent the contact 97 and a conductor 100 extends from said contact 99to the primary 101 of the induction coil, and from said primary to the conductor 94. The secondary coil 102 is connected at one terminal to the contact 99 and at its other terminal to the receiver 103, the other terminal of the receiver being connected by means of a conductor 104 to the main lead 83. These constitute the talking and listening circuits and are conventional except for the provision of contacts 87, armature 41 and contact yoke 36 therefor.

Theelectromagnet 37 which is mounted in the yoke 36 may be termed the connector magnet, and the circuit in which said magnet is located maybe termed the connector circuit. This circuit includes a conductor 105 leading from one terminal of said magnet to the brush 72 of the generator indicated generally at 106. The other terminal of the electro-magnet 37 is connected by means of a conductor 107 to the plate 60 of the multiple plate switch mentioned above. The plate 61 is then connected by means of a conductor 108 with the, other brush73, of the generator.

The electro-magnets 26 are located in what may be termed the selecting circuit, the mechanisms operable by said electro-magnets, are for the purpose of selecting a station on the party line to be called. The coil 28 of said electro-magnet 26 is connected by means of a conductor 111 to the contact 81 of the reversing switch described above, said contact 79 being connected b means of a conductor 110 to the contact 7 9 of said reversing switch, in the usual manner. The coils 27 and 28 of the magnet 26 are connected together in series, and the coil 27 is connected by means of a conductor 109 to the middle contact ,80 of the reversing switch. The plate 78 of the reversing switch is then connected by means of a conductor 113 to the short plate 50 of the multiple plate switch and the long plate 58 thereof. The plate 77 is then connected by means of a conductor 114 with the ground .115. A branch 116 is then taken from the conductor 113 and led to the conductor 104 or the main lead 83 as desired. The conductor 105 is provided with a branch lead 117 which is connected to the short plate 56 of the switch. A contact 118 is provided beneath the receiver hook 84 for contact therewith when the receiver is upon the hook, and said contact 118 isconnected by means of a lead 119 to the short plate 45 of the switch. The brush 74 which bears upon the collector ring of the generator is connected by means ofa lead 120 with the short plate 46 of the switch, and the brush 75 or ground of the generator is connected by means. of a conductor 121 with the short plate-51 of the switch. It is also to be noted that the short plate55 of the switch is connected across-to the longplate 60 by means of a connector 122. The plate 59 of the switch is then grounded by means of a conductor 123 to the ground 115 as indicated. Finally, a polarized bell 124 is provided having one terminal connected to the main lead 83 and the other terminalconnected by means of a lead 125 to the contact 118 which is located beneath the receiver hook. r j

In'operation, and assuming that station A is about to call up station B, thefirst step is to energize the connector circuit of station A which can be done by pressing the button 67 y of the multiple plate switch, and then operate the magneto generator.

As a result a current travels from the brush 72 of the magneto generator, through the conductor 105 to the magnet 37 energizing the same, returning through the conductor 107to the long plate 60 of the multiple plate switch, which long plate will now have been contactedwith plate 61 by movement of the button 67 whereby the current may return through said plate 61, and the conductor'108 connected thereto to the brush 73 of the generator. The electromagnet 37 having been energized, its spring armature 41 will be attracted and held down thereby completing the circuit between the conductor 91, through the armature into the yoke 36. As soon as this connection is established, continued energization of the generator will cause a current to pass from the brush 72 through the conductor 105 and into the branch 117 connected to said conductor 105 into the short plate 56 of the switch. This plate being in contact with the plate 59, because of the depression of the button 67, the current will enter said plate 59 and thence into the conductor .123 and to the ground 115. The current will then enter at the ground 115 of'station B, and through the blade 77 of the reversing switch of said station into the conductor 111 of said station entering the electro-magnet 26, returning through the conductor 109 leading from said electro-magnet, to the reversing switch, through the blade 78 of said switch, through the "conductor, 116, returning through the main lead 83 to station fA, entering station A by means of the conductor 116 thereof, and .from said conductor 116 through the conductor 113 into the plate 58 of the switch of. said station which blade will now be contacted at its right hand terminal with the righthand end of theplate 52 owing to the fact that depression of the button 67 released the tensionon the spring 52 so as to permit the same to descend and contact with said plate 58. The current passing through the spring 52 enters the short blade 55 thence traverses the short connector 122 into the long blade 60,-and thence intothe right hand terminal 63 of the blade 61, leavingsaid blade 61 and returning to the generator bymeans of the conductor 108. Thus it will be seen that both selecting magnets 26 of the station will be energized simultaneously andto thesame extent. The generator sending out a pulsatingcurrent through the brushes 72 and 73 intermittently energizes the magnets 26 so as to vibrate the armature 30 thereby causing rotation of the ratchet 20 and consequently movement of the hand 13 over the dial. When the calling subscriber has observed that the hand has arrived at the number on the dial corresponding to that of the subscriber called, further actuation of the generator is stopped. The cam 89 of the called subscriber will then be in a position to close the contacts 86 and 88. The cams of the other subscribers sets will not be in a position to close the contacts. It will also be observed that owing to the fact that the magnet 27 of the electro-magnet 26 of the calling subscriber is energized, the blade 39 will have been shifted over the blade 41 thereby retaining the spring armature 41 in contact with the pole of the magnet 37.

The subscriber having been selected, his bell may be rung by sending an alternating current through the main lead which can be accomplished by firstreleasing the button 67 and then reactuatingthe generator, whereupon a circuit will be established which will permit an alternating current to pass from the collector brush 74 through the conductor 120 to the short plate 46 of the switch through the plate 42, to the short plate 45, thence through the conductor 119 into the receiver hook passing therefrom through the conductor-85 and through the conductor 90, yoke 36, armature '41 and wire 91 to the main lead 82. The current enters station B from the main lead 82 through conductors 91, and 92, through the closed contacts 86 and 88 throughthe conductor 85 into the receiver hook 84, contact 118 and through conductor 125,through the bells 124 of station B, passing out through the main lead 83 to station A. The current returns to station A by means of the conductor 104, through conductor 116, conductor 113 to the short plate 50 of the switch, through the long plate 47 to the short plate 51, and leaving said plate 51 through the conductor 121 returning to the ground contact 75 of the generator. Thus, it will be seen that only the bell of the called subscriber can be rung inasmuch as it is only that subscriber that'has the contacts 86 and 88 in engagement by reason of the operation of the selected mechanism.

Considering the voice current originating in station B the cur e t from the b t ery 98 traverses the transmitter 95, conductor 94, passing through the primary 101 of the induction coil and through the contact 99 to the receiver hook 84, thence through the lead 85 closed contacts 87, conductor 92 and through the conductor 91 tothe main lead 82. In the station A, the current is received through the conductor 91, armature 41, yoke 36, conductor 90, contacts 86 and through the conductor 85 to the receiver hook 84 and thereby through the secondary 1020f the induction coil, thence to the receiver 103 and to the main lead 83 through the conductor 104.

To return the selecting mechanism to normal position after conversation I has ceased, the calling subscriber in the present instance A, depresses button 66 and then energizes the generator, first sliding the generator shaft longitudinally soas to actuate the reversing mechanism. A direct current then leaves the brush 72 of the generator, passing through the conductor 117 into the short plate 56 .of the switch. Through the long plate 52 into the plate 58 owing to the fact that depression of the button 66 permitted engagement between the plates 52 and 58, thence through the conductor 113 to the switch blade 78 of the reversing switch, into the contact 81, through the conductor 111 into the magnet 26 thereby energizin them and reversing their polarity relatlve to the polarity which was acquired in the first instance when energized by current sent through the reversing switch priorto its actuation just'mentioned. The current then leaves the magnet through the lead 109, entering the contact 80 of the reversing switch, passing through the switch blade 77 into the ground 15 and also through the conductor 123 to the switch blade 59, through the short plate 55, traversing the short connector 122 to the long plate 60 through the plate 61, returning to the brush 73 by way of the conductor 108. By reversing the polarity of the magnet 26, the pole 28 will be energized so as to attract the armature 30 toward said pole whereupon the lever 21 will be reciprocated to an eX- treme position so asto disengage the pawls 23 by reason of their engagement with the stop 25 so that a coil spring 126 encircled ing subscribers being locked out. It will be apparent however, that each and every one of the subscribers will be aware when the line is in use and when the conversation between subscribers has ended and the line is again open.

While I have illustrated and described my invention with some degree of particularity, I realize that in practice various alterations thereover may be made and I therefore desire to reserve the right and privilege of changing the form of the details of construction or otherwise altering the arrangement of the correlative parts without departing from the spirit of the invention or the scope of the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. In a party line telephone system, the combination with a pair of main leads and a plurality of receiving and transmitting sets connected thereby, a normally open switch in each set disconnecting said set from the said leads, a polarized step by step magnetic means for each switch to close the switch when energized by alternating current, a reversing switch, a generator adapted to generate direct and alternating currents and in series with the said reversing switch and the said magnetic means, a multiple contact switch, circuits connecting said generators, magnetic means and said normally opened switches, and a, means associated with each magnetic means operable when a direct current from said generator is generated to restore the step by step mechanism to initial position and thus open the switch.

2. In a party line telephone system, a talking'and listening set, a pair of main leads, a normally open relay in series with the leads and set, a generator adapted to generate direct and alternating currents in circuit with the magnetic means of the relay, a plurality of step by step mechanisms each including a pair of polarized electrical magnets and an armature, the latter oscillating toward one pole when the electrical magnets are energized by an alternating current and attracted to the other pole when the electrical magnets are energized by a direct current, a locking means for the rela operable when the armature is oscillated w ereby the talking and listening sets may be locked in closedcircuit with the main leads, a second talking and listening set adapted to be placed in circuit with the main leads when the step by step mechanisms reach a predetermined point of operation, and means operable when a direct current is generated and the armature thus attracted to release the step by step mechanisms to restore them to zero, and to release the locking relay.

In testimony whereof I afiix my signature in presence of two witnesses.

ELMER CURNUTT.

Witnesses ERNEST L. HoLMns, J OHN STEWARDSON. 

